From DE 196 50 258 A1 a method is known, with which the properties of a metal part are modified on the surface by laser alloying. The alloying components are supplied in the form of rods or wires. Following the laser alloying, the modified regions are usually not difficult to distinguish from unalloyed regions, since during the supply of material by the rod or wire that is locally closely limited it can hardly be avoided that irregularities remain on the surface of the plate.
In the application DE 10 2014 010 660.8 a method is described, with which the properties of a plate are locally modified, in that an amorphous mass containing an alloying element is locally placed onto the plate and heated together with the plate in order to alloy an alloying element contained in the mass into the part of the surface of the plate covered by the mass, while the uncovered remainder of the surface remains unalloyed. Since the amorphous mass can be applied over a large area but in a substantially thinner layer than with a rod or wire, such a treatment does not necessarily leave behind visible traces on the surface of the plate which make possible an unambiguous distinction of alloyed and unalloyed regions from one another. This makes it difficult to take into account the position of the alloyed regions during the further processing of the plate. However, when the position of the alloyed regions is not taken into account there is a high probability that a subsequent processing step is performed on a surface region which is not suitable for this, so that the processing fails or results in a product that is defective in quality.
Accordingly, there is a need for a method with which it can be ensured in a simple and reliable manner that processing steps are performed on the surface regions provided for this purpose.